jumps several pages

[jo2904]

What went wrong?

When reading CBZ files in continuous scroll mode (webtoon/infinite scroll), the reader
suddenly jumps several pages forward with no apparent reason — for example jumping from
page 20 to page 40 during what felt like normal scrolling. It happens randomly, not always
at the same spot in the file, and I've seen it on both desktop and mobile browsers. No error
shows up in the container logs at the time of the jump.

Might be related to the off-screen image eviction strategy introduced in #433 for the infinite-scroll reader — if evicted placeholders don't match the real image height exactly, the browser recalculates scroll position and jumps.

How can we reproduce it?

1. Open a CBZ in the reader, using continuous scroll mode (infinite scroll)
2. Scroll down normally while reading
3. At a random point, the view suddenly jumps forward by roughly 15-20 pages (e.g. page 20 → page 40)
   with no action on my part

What happened: the reading position suddenly jumps forward by dozens of pages during normal
scrolling, unpredictably.
What you expected: continuous, page-by-page scrolling with no jumps.

What Build of Grimmory are you on?

Stable

Your setup

• Grimmory version: v3.2.4
• How you're running it: Docker (via Portainer / docker-compose)
• Browser: desktop and mobile (Firefox)
• Operating system: (fill in per device)

Screenshots or error messages (optional)

No visible error in the application logs at the time of the page jump (checked 48h of logs, no WARN/ERROR entries related to the reader/CBX).

Before submitting

• I've searched existing discussions and this hasn't been reported yet
• I've reviewed this report and have completed it as fully as I can